Sandblasting is the process of forcibly propelling a stream of abrasive media against a surface under high pressure to put smooth or rough texture on a surface, shape a surface, or remove surface contaminants. Compressed air or a centrifugal wheel is used to propel the media.
Bead blasting is the process of removing surface deposits with the use of fine glass beads propelled at a high pressure without damaging the surface.
Wet blasting is basically, any wet blast system uses water with abrasive to form the slurry that is used for the blast effect. The velocity of the slurry along with the physical characteristics of the blast media is what does the cleaning or peening.
This has the dual advantage of lowering media breakdown rates and preventing impregnation of foreign materials into the surface. Hence surfaces after wet blasting are extremely clean, there is no embedded secondary contamination from the media or from previous blasting processes, and there is no static cling of dust to the blasted surface.